1. Field of the Invention
The present invention relates to topical compositions for transdermal administration. More particularly, the present invention relates to pharmaceutical compositions for nourishing and improving skin and for treating acne, comedo and zit.
2. Description of the Prior Art
Human skin structure consists of epidermis, dermis, subcutaneous fatty tissue, sebaceous gland, sweat glands, and hairs. The thick layer under the epidermis is the dermis. The hairs are surrounded by hair follicles, which have associated sebaceous glands. The sebaceous glands can secrete sebum, which will permeate to the surface of the skin by the hairs and hair follicle, and then becomes fatty film. The fatty film will attach to the surface of the skin and protect the skin. Skin types may be classified according to the quantity of sebaceous glands as oily skin, dry skin, and mixed-type skin.
Acne is a chronic inflammation in the hair follicle and the sebaceous gland. Acne is also commonly known as comedo or zit. It is usually found on the forehead, around the nose wing, and on the cheeks. It can also be found on any part of the body with hair follicles, such as the back, thoracic part, and thigh. Depending on the symptoms, acne can be classified as acne-type, inflammatory and red swelling type, and cyst-type. When gonads of adolescents mature, androgenic hormone in the testes and ovaries increases Androgenic hormone stimulates the sebaceous glands. As a result, the sebaceous glands become hypertrophic and secrete abundant sebum, which accumulates around the sebaceous glands and hair follicles. The accumulated sebum may become infected by bacteria. Usually, acne with a white or black head is formed first; it subsequently becomes papule, pustule, node and cyst after bacterial infection. Finally, a zit is formed. When too much androgenic hormone is secreted, redness, tickle, heat, burning sensation, and skin peeling may occur around the T area of the face or the skin under the eyelids. This sometimes leads to seborrheic dermatitis, which is characterized by the appearance of visible microvessels.
To prevent these problems, topical preparations are needed to clean the skin, kill the bacteria, prevent water evaporation, and improve moisture retention. Examples of topical preparations for these purposes include a cream containing sodium chloride for mollifying and soothing the skin disclosed in U.S. Pat. No. 3,574,854, and a skin-care composition containing mineral salts disclosed in German patent publication No. DE 3,327,840. Furthermore, U.S. Pat. No. 3,859,436 disclosed a glucose mixture for soothing skin, and U.S. Pat. No. 3,777,597 disclosed a shaving aqueous solution comprising glucose.
Sodium Chloride, especially 0.9% sodium chloride solution, i.e., saline, is the main composition in maintaining the osmotic pressure of body fluids. A solution containing a higher concentration of sodium chloride cannot be absorbed by the skin. Instead, it will irritate the skin mucosa and results in dehydration. Thus, topical preparations containing sodium chloride may irritate skin or kill bacteria. However, sodium chloride can hardly prevent water evaporation from skin or improve moisture retention. Glucose may increase glycogen, ensure cellular functions, improve metabolism by functioning as a nutritional agent. In addition, it may function as a detoxification agent. However, these effects cannot be achieved by applying the topical preparations containing glucose to the skin. Instead, glucose must be administered orally, intravenously and intramuscularly to have these effects.
There have been many therapeutic agents and cosmetics for treating various skin conditions, such as Hydrocortisone for treating atopic dermatitis with titillate and erythema, sulconazole nitrate for treating mycotic infection in the skin, tretinoin for treating light-induced aging, and 5-fluorouracil for treating psoriasis and skin cancer. Therapeutic agents for use in treating dermatologic diseases usually include permeation enhancers, such as dimethyl sulfoxide (DMSO), dimethyl formamide, methyldecyl sulfoxide (U.S. Pat. No. 3,527,864), dimethyl acetamide (U.S. Pat. No. 3,472,931) and N-alkyl-2-pyrrolidone (U.S. Pat. No. 3,696,516). However, the above-described permeation enhancers have certain disadvantages. For example, dimethyl sulfoxide has some odor and body odor, can burn the skin and induce erythema on skin, can reduce the transparency of crystalline-skin, and can even cause tissue necrosis in the animals. (Martindale, The Extra Pharmacopoeia, pages 1461-1463, 27th Ed., 1977). Dimethyl formamide and dimethyl acetamide can also burn the skin and induce erythema on skin.
Moreover, Trebosc et al.(U.S. Pat. No. 5,030,451) disclosed a cosmetics composition containing improved derivatives of caffeine as active ingredients. The formulation has excellent and long-acting “lipolytic” properties and has proven very effective in weight loss programs and in the treatment of cellulite. An anti-cellulite composition containing methylsilanol theophyllin acetate alginate and methylsilanol mannuronate is disclosed by Mausner in U.S. Pat. No. 5,215,759. In U.S. Pat. No. 5,051,449, Kligman disclosed a method of reducing cellulite by locally applying retinoid to skin. Kligman reported that the treated subjects have a thickened epidermis and an increased number of new blood vessels, with a moderate to noticeable degree of improvement in the pinching test.
Topical aminolevulinic acid-photodynamic therapy for the treatment of acne vulgaris is disclosed in U.S. patent application No. 20020099094 A1. U.S. patent application No. 2002006185 A1 disclosed a composition for treating acne comprising water and glycol, and U.S. patent application No. 20010056071 A1 disclosed a composition for treating acne comprising resveratrol (3,4′,5-trihydroxy-trans-stilbene), melatonin, Vitamins D, E, and A.
In addition, Shapiro, S. S. and Saliou, C. described that vitamin A, vitamin D and their derivatives in combination with vitamin C, vitamin E, and coenzyme Q could improve skin conditions and cure acne (Nutrition 2001, Vol. 17(10), pages 839-844). Vitamin A acid (i.e., Tretinoin or Retinoids) is a derivative of Vitamin A, and its major function is to remove cutin because it can remove the cutin on the epiderm. In addition, it can alleviate occlusion of the pores, reduce wrinkles and improve blood circulation around the face, decrease scar of pigment, and prevent skin keratinization, promote refreshing and sloughing off of epithelium cells, prevent synthesis of keratin, and prevent the formation of blister on the face. However, most Vitamin A acid-containing products may make the skin sensitive to the light, and overuse of these products may cause side effects, such as dry, red swelling, itching and dermatitis, etc.
From the foregoing, although there are patents disclosing compositions for the therapy of acne, decomposing fat or treating various skin symptoms, all these compositions have some defects and may do harm to the skin. Accordingly, the present invention provides a Vitamin A acid-free topical composition for transdermal administration.